Caffeine negatively impacts sleep: Study

By ingesting coffee to stay awake and feel energetic, night-shift workers may be digging a hole for themselves, for caffeine, a key ingredient of coffee, has a negative effect on people's bodies during the subsequent day as well.

Study finds negative impact of caffeine
Julie Carrier, a psychology professor at the University of Montreal and lead author of the study, along with her colleagues analyzed the impact of caffeine intake on 24 participants.

These 24 participants were divided into two age groups. The first group consisted of those between 20 and 30 years, while the other group had participants aged between 45 and 60.

The researchers took an account of the participant’s sleep durations, slow-wave sleep (SWS), and rapid-eye movement sleep (REM) after administering them caffeine pills.

These participants were not allowed to sleep until they had spent two sleepless nights inside the lab. Thereafter, both the groups were given either 200 milligrams of caffeine or a lactose based placebo.

The study found that participants who had been given the caffeine pills, especially the ones in the older age group, slept close to 50 percent less than usual.

Overall, the caffeine negatively affected the sleep during the subsequent day. The sleep of those who had ingested coffee was less efficient, shallower and was characterized with decreased durations, slow-wave sleep (SWS), and rapid-eye movement sleep (REM).

The advice
“Caffeine is the most widely used stimulant to counteract sleepiness, yet it has detrimental effects on the sleep of night-shift workers who must slumber during the day, just as their biological clock sends a strong wake-up signal. The older you get, the more affected your sleep will be by coffee,” noted Carrier.

“We all know someone who claims to sleep like a baby after drinking an espresso. Although they may not notice it, their sleep will not be as deep and will likely be more perturbed,” added the researcher.

The researchers recommended that those aged 40 and above should reduce their caffeine intake drastically.

The findings of the research, which was partially sponsored by the Canadian Institutes of Health Research, appear in the latest issue of the journal Sleep Medicine.

The researchers cautioned that since the study was conducted in a lab and that too with few participants, further detailed research is needed to authenticate the results.